全文获取类型
收费全文 | 1084853篇 |
免费 | 72599篇 |
国内免费 | 1377篇 |
专业分类
耳鼻咽喉 | 15113篇 |
儿科学 | 35038篇 |
妇产科学 | 28935篇 |
基础医学 | 154887篇 |
口腔科学 | 29866篇 |
临床医学 | 95969篇 |
内科学 | 205675篇 |
皮肤病学 | 24502篇 |
神经病学 | 82536篇 |
特种医学 | 43420篇 |
外国民族医学 | 201篇 |
外科学 | 164127篇 |
综合类 | 21832篇 |
现状与发展 | 1篇 |
一般理论 | 270篇 |
预防医学 | 75554篇 |
眼科学 | 24717篇 |
药学 | 86789篇 |
7篇 | |
中国医学 | 2817篇 |
肿瘤学 | 66573篇 |
出版年
2019年 | 7921篇 |
2018年 | 11479篇 |
2017年 | 9073篇 |
2016年 | 10275篇 |
2015年 | 11444篇 |
2014年 | 15496篇 |
2013年 | 22586篇 |
2012年 | 31074篇 |
2011年 | 32900篇 |
2010年 | 19248篇 |
2009年 | 18106篇 |
2008年 | 30438篇 |
2007年 | 32520篇 |
2006年 | 33178篇 |
2005年 | 31471篇 |
2004年 | 30156篇 |
2003年 | 28930篇 |
2002年 | 27883篇 |
2001年 | 60348篇 |
2000年 | 61788篇 |
1999年 | 51239篇 |
1998年 | 12580篇 |
1997年 | 11114篇 |
1996年 | 11112篇 |
1995年 | 10430篇 |
1994年 | 9455篇 |
1993年 | 8952篇 |
1992年 | 38002篇 |
1991年 | 36502篇 |
1990年 | 35919篇 |
1989年 | 34481篇 |
1988年 | 31036篇 |
1987年 | 30131篇 |
1986年 | 28345篇 |
1985年 | 26563篇 |
1984年 | 19294篇 |
1983年 | 16209篇 |
1982年 | 8878篇 |
1979年 | 17100篇 |
1978年 | 11461篇 |
1977年 | 10288篇 |
1976年 | 8889篇 |
1975年 | 10125篇 |
1974年 | 11733篇 |
1973年 | 11321篇 |
1972年 | 10797篇 |
1971年 | 10155篇 |
1970年 | 9306篇 |
1969年 | 8989篇 |
1968年 | 7954篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
K Ohtsuka K Tsuji Y Nakagawa H Ueda O Ozawa T Uchida T Ichikawa 《Journal of nutritional science and vitaminology》1990,36(3):265-276
O-beta-D-Galactopyranosyl-(1----4)-O-beta-D-galactopyranosyl-(1----4)-D- glucopyranose (designated as 4'GL) is produced from lactose by Cryptococcus laurentii. The influence of chronic ingestion of 4'GL on body weight gain, organ weight, serum lipids, and liver lipids was investigated in rats. The body weight gains of the 5% and 10% 4'GL-diet groups were higher than that of the control group. Food intake and fecal dry weight were significantly increased (p less than 0.05) by 4'GL feeding. The 4'GL diet produced a significant increase (p less than 0.01) in the wet weight and contents of both the cecum and the colon. However, no significant increase was observed in the weight of the stomach, small intestine, liver, or other organs. The effects of 4'GL on serum and liver lipid levels were not observed in this experiment. The digestion of 4'GL was measured in vitro using the artificial gastric juice, alpha-amylase of human saliva, alpha-amylase of hog pancreas, and mucosa of rat intestine. 4'GL was not hydrolyzed by these enzymes. Long-term ingestion of 4'GL did not cause any induction of 4'GL hydrolyzing enzyme activity in the rat small intestine. 相似文献
972.
973.
F Salomon R K?rprich J Biscoping J Strobel 《Klinische Monatsbl?tter für Augenheilkunde》1990,196(1):26-29
Local anesthetics injected retrobulbarly are detectable in the aqueous humor. From 40 patients who received a total dose of 140 mg lidocaine, 15 mg bupivacaine, and 30 mg etidocaine, samples of aqueous humor were taken between 30 and 90 minutes after administration (average 57 minutes). The mean lidocaine concentration was 1.02 micrograms/ml, that of bupivacaine 0.075 micrograms/ml. Etidocaine, used only for facial nerve block in front of the ear, could not be detected in the aqueous humor. All three substances were found in the central venous blood. It therefore appears unlikely that any of them are transported via the blood-aqueous barrier, whether actively or passively. Local anesthetics can inhibit corneal cell proliferation and result in lens opacification when administered into the conjunctival sac. It may be that local anesthetics detected in the aqueous humor have similar effects resulting from contact with the cornea and lens. 相似文献
974.
A new method of refractive corneal surgery is presented. With the q-switched Nd:YAG-laser Visulas (Zeiss-Oberkochen) we succeed in altering the optical power of the cornea of rabbits, pigs and humans. The number of applied laser spots and the distribution pattern influence the way and the amount of change of refraction. The method, clinical and histological features, complications and prospects of the Nd: YAG laser keratorhexis are described. 相似文献
975.
Lifetime toxicity/carcinogenicity studies of FD & C Blue No. 1 (brilliant blue FCF) in rats and mice
FD & C Blue No. 1 was fed to Charles River CD rats and CD-1 mice as a dietary admixture in lifetime toxicity/carcinogenicity studies. The rat study was conducted with an in utero phase in which the compound was administered to the F0 generation rats (60/sex/group) at dietary concentrations of 0.0%, 0.0%, 0.1%, 1.0% or 2.0%. After randomly selecting the F1 animals, the lifetime phase was initiated at the same levels with 70 rats/sex/group, including two control groups. The maximum exposure times were 116 and 111 wk for males and females, respectively. The no-observed-adverse-effect levels are dietary concentrations of 2.0% for males (1072 mg/kg body weight/day), and 1.0% for females (631 mg/kg/day) based on a 15.0% decrease in terminal body weight and decreased survival in the high-dose females compared with the combined control groups. Charles River CD-1 mice (60/sex/group) were fed FD & C Blue No. 1 as a dietary admixture at levels of 0.0%, 0.0%, 0.5%, 1.5% or 5.0% in a lifetime toxicity/carcinogenicity study. The maximum exposure time was 104 wk for both males and females. No consistent, significant compound-related adverse effects were noted. The no-observed-adverse-effect level established in this study is a dietary concentration of 5.0% (7354 mg/kg/day and 8966 mg/kg/day for male and female mice, respectively. 相似文献
976.
J. W. G. Tiller K. P. Maguire B. M. Davies J. T. Dowling L. H. Tung M. J. Rand 《Human psychopharmacology》1990,5(4):313-321
Five out of 12 physically healthy patients with depression undergoing a tyramine pressor test developed cardiac arrhythmias. These arrhythmias occurred in drug-free patients in three out of 12 infusions following as little as 0.03 mg/kg of tyramine and after moclobemide, a reversible inhibitor of monoamine oxidase-A, in four out of 14 tyramine infusions with as little as 0.04 mg/kg of tyramine. The arrhythmias seen were independent of patient's age and occurred both before and after 30 mmHg elevations in systolic blood pressure. Electrocardiographic abnormalities and arrhythmias seen were a loss of p waves, sinus tachycardia, frequent atrial ectopic beats, atrial premature beats, Wenckebach phenomenon, junctional rhythm, ventricular ectopics, varying QRS configurations, and ventricular bigeminy. Tyramine, both oral and intravenous, caused similar reproducible changes in dogs, though not in rats, mice or guinea pigs. Practical implications are that tyramine pressor testing in humans should be performed cautiously and only with adequate cardiac monitoring and resuscitation facilities at hand. These findings suggest that a normal dietary component can induce serious cardiac arrhythmias, and that a low-tyramine diet may be of value for patients who are susceptible to cardiac arrhythmias. 相似文献
977.
We present a series of 41 diabetic patients with severe tissue destruction and deformity secondary to hand infections. Thirty (73%) of the patients showed propagation of the infection to bone, tendons, or deep palmar spaces, and 26 of 41 (63%) required amputations. Sixty-three percent of the cultures were mixed; pure Staphylococcus aureus accounted for only 12%. Diabetics who were renal transplant recipients were at increased risk, with a 100% amputation rate and an average hospitalization of 41 days. Recommendations for management of diabetic hand infections are given to reduce the mortality and morbidity in these patients. 相似文献
978.
979.
E M Sacks L L Fajardo B J Hillman G W Drach J A Gaines H R Claypool N J Clinger D J Fillmore K R Hunt G D Pond 《The Journal of urology》1990,144(6):1341-1346
Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients. 相似文献
980.
A nephron-sparing operation recently has been shown to provide extended survival free of disease in selected patients with localized renal cell carcinoma, particularly for tumors of lower stage. To define better the role of conservative surgical treatment in more locally advanced renal cell carcinoma we reviewed 9 patients with venous tumor involvement in solitary functioning kidneys who underwent a nephron-sparing operation. Complete tumor resection with adequate preservation of renal function was accomplished in all cases. Of the 9 patients 5 had no evidence of disease 7 to 93 months (mean 33.2 months) postoperatively. The remaining 4 patients died of metastatic renal cell carcinoma 17 to 47 months (mean 35.5 months) postoperatively, 2 of whom had concomitant local recurrences in the renal remnant. Based on previously reported results of total nephrectomy for renal cell carcinoma with venous involvement and the morbidity associated with renal replacement therapy, we believe that a nephron-sparing operation is a viable option in the management of these patients. 相似文献